Surface finishing



Aug. 12, 1947. R. c. PRUITT Er AL I 2,425,640

SURFACE FINISHING Filed April 23, 1945 3 Sheets-Sheet 1 Aug. 12, 1947.

R. C. PRUITT ET AL SURFACE FI NISHING Filed April :25, 1945 5 Sheets-Sheet 2 12,1947. R. c. PRUITT Er M.v 2,425,640

SURFACE FINISHING Filed April 25, 1945 v 3 sheets-sheet 5 DM-OLS lf2 /0/ loo\SIf\-RT .STOP

Tang/W CRG H CRIIE AIR soLsea, CR 5a,

Am su. 93a. cR1 b P* Mfg GEAR so|..eo 4PCRM.

IZZ C426 m me/www5.

Patented Aug. 12, 1947 SURFACE FINTsHlNG Rodman C. Pruitt, Seymour, Ind., and Edward F. Fowle and Richard S. Iglehart, Springfield, Ohio, assignors to The Steel Products Engineering Company, Springfield, Ohio, a corporation of Ohio Application April 23, 1945, Serial No. 589,786

12 Claims.

This invention relates to the smoothing of the sharp edges or surfaces of articles such as gears and the like.

It is the principal object of this invention to provide a simple, rapid and accurately controllable method of removing the burr or wire edge, or of smoothing or breaking the surface of metal, plastic or other articles such as gears and .the like to provide a smooth, uniform surface thereon.

It is also an object to provide a machine for accomplishing such burring, breaking, or smoothing which is rapid in its action, relatively simple and easy to operate, and which produces consistent and uniform results.

It is also an object to provide such a machine which can be readily controlled to produce the desired removal of the burr, wire edge, or the like,but without removing other material from theface of the article or otherwise impairing the desiredsurface thereof.

`,It is also an object to provide such a machine in which the action can be readily controlled and predetermined through suitable selection of the several vvariable factors present to developA the desired actionjin predetermined selected areas, leaving other'portions of the metal piece substantially unaffected. vOther objects and advantages will be apparent from the following description, the `accompanyingdrawings and the appended claims.

'In the Vdrawing-Q- I Fig. `1 'is a view in perspective of a machine constructed in accordance with the present invention;k

Fig. 2v is la side elevational view of suchv ma- .chinewith certain of the drive mechanism being shown iny section and with the pot or tank being shown in three (3) diierent elevated positions; FigfS is a front elevational view of the machine also showing certain portions thereof in section;v N-1Fig. 4 is a planvview lookingdown upon the machine" with part of the housing being broken away. showing the arrangement of the reversing drive mechanism; Fig. 5 is a vertical section view on the broken A.line 5f-.5A of Fig. 4 showing the gear train for one direction of rotation.; Fig. 6 is a vertical sectional viewon the broken lineLB-f of Fig. 4 showing the gear trainfor the 'opposite direction oflvrotation; v

Fig. 7 is agplanviewuof-:the reversing plate for iselectingvone or the other of the two gear trains; Y. lfigpzl'is a detailed-perspective view ofA a removable baiile member which may be introduced into thev tank in order to provide additional control over the burring action; and

Fig. 9 is a circuit diagram providing for the automatic control of the machine.

Inmany machine operations the work piece whenA formed on the machine is left with burrs, a wire edge, or with a sharp edge, any or all of which are usually undesirable and which must therefore be removed before the piece is in condition for ultimate assembly and use. This occurs commonly in the production of gears, the customary milling operation for forming the gear teeth usually leaving an objectionable burr along the edge of the teeth, often extending into the bottom of the space between the the teeth. This is particularly objectionable in the production of gears and the like from extremely hard metal, in which case it becomes necessary to process all such ar-ticles subsequent to their actual cutting in order to remove such burr, wire edge, or the like. For precision work this operation frequently is done by hand, with a skilled operator using a burring tool against both upper and lower edges of the formed teeth, an operation which it will be understood is one requiring a high degree of skill, and involving a considerable period of time, usually much greater than the time required in the initial cutting of the teeth, and thus materially increasing the cost ofthe finished article.

In accordance with this invention a machine is provided which rapidly and accurately performs such burring and smoothing operations under controlled conditions which provide a high degree of initial accuracy asto the extent of the burring which is elfected, and likewise which can be carried out with great uniformity so that a series of articles may be finished in a substantially identical manner. The possibility of variations occurring in any one article, and between a series of articles, is thus largely overcome, as is likewise the need `for a highly skilled worker to perform such an operation. The machine itself provides for uniformity and properly controlled smoothing and hurling, and is so constructed that it may be readily operated in' an entirely satisfactory manner by an unskilled worker.

In addition to the elimination of the individual skill ofthe workman, the machine provides for smoothing the edges of all the teeth, both upper and lower edges, at the same time, and further may conveniently be constructed to provide for the treating of a group of articles simultaneously. Furthermore the entire operation for smoothing or burring the group of articles requires only a small fraction of the time usually required forv performing a hand operation upon one such article.

and on which there is mounted the adjlisjgableV pulley 2| forming the driving element of a va'i able. ratio, drlve- For Plifpses .Qi .illustration ille RQYSYPQ dll?? 111 i a vhand wheel 22 juste@ .te Chang the 'Spad sheaves of the'drive' there isV recelye'l @he The driven lrfle'm 2,5 and@ mevklesll urged s ing 21 t`o ard the @was the. g. retire# were.

the drive sou an durch soiefriid., "s u secured with theu'se style E-.EI @9212, ,Stearns megestiflutell braga.. .l

. ,mated inw. tva raised. PSlll.

axis of shaft 36 and the plate is thus free to oscillate upon its support about shaft 36. It carries an outwardly extending arm 59 which may be manually operated to shift from one position to another. Preferably however a pair of solenoids and @I arel arrangedto. he. seletiyely actuated to shift Ythe 'plate between its two positions.

Two sets of drive gears are carried by the plate 53 at different levels. The upper set comprises the 'gear l62`meshing with gear 50 and mounted on plate 3 by means of an upwardly extending "in F3, and which 'is Yadapted to have meshing en- "drivenpinion 65 fixed tothe d"The lower set carried on plate I53 includes a pair of gears', 1T which are mounted thereon r `positionf`tdengage the lower drive gear 5|. in turn to be engageable with a driven pinion `l3`,"'al`s"oixed to driven shaft 66. The mounting 0f .the tw@ .gear .trains iS wel; that .es .Siler/e. lll Fig. only one 'setl fc. n'bein ing rel nv'vitlg s'h'aft attbe same time. 'As'fsho w figure, the gear train comprising ge A pinion Gland the drivenV E'Sfprovd' drivin'g`-sfhaf`t one this Ati'rne'th'e alter ate gear 51, and" the" rotating freely,

. pfllrl'llhlllfg Gill eff tlsll W driven pinion 1-31 `Whenhowever"rotation` in the Oppositey direction. is. dslredrih? plate. 5.3. ls. 'Ird either manuallyf yor aut u A gela? Lfl.S's.flflllis there@ urlwrcl vlse, direction es Shown, lull-le- `4 Loli fes. dsengaging gears `62arlnd Iand establis g driving engagement bet-we resulting ln. dill a s but lllllle'epie@ t .l the Seite ,stessi provided 'with 'hearings 1s; e. bracket. 1.1 Supportegflfr 12--of the machine. Theish Die@ fpnsisi .g Ojff gears.. shown they are'V re'ferably spaced s qmewh @eeh other. by .means Qf sali llaS'Lll-..

The freme'lz f'th chi verticallyfextendmgw, s g5 receive thereon a rear slide 86. .ed Qn .the rear slide.. i5, .isanl' fr; rit'. Slide. riidovideslf "a'rhiohv there is 'detachably secured the. p

nel; that.. while, .reni urely'; held.' "against, more: entered by the two slides; suchfmeans being` showny as an air cylinder l? @patrolled by. all caillngjthe rais." garfl 86;- vlili restes# t9.' 'the chine.'y Similarl Vair cylirderQQconutrolle air.valve,96 providesr for raisingandflg in V-o'f the beit willfbe dearth leifatiqns., 'Silflll elevation." proximately bythe des* i' spiectively in Fig. `2,`re'ferr1ng `tothe p maremma-tileeak-fhhe f 'Tank SI2 isfadapte'd 'to' conta h the vary as to its own characteristics and also may be prepared in suspensions of different viscosity and other physical characteristics as desired to bring about the proper results in operation. As an example, highly satisfactory results have been secured where the abrasive consisted of No. 12, No. or No. 30 silicon carbide grits, the No. 20 size having beenvfound to be preferable for most purposes. Such abrasive is mixed with a iiuid suspending vehicle which will have sufficient viscosity to suspend the abrasive and such body as to retain the abrasive in working contact with the relatively moving surface of the article as required to work off the burrs and wire edges. Preferably a relatively heavy oil is used as the vehicle, a suitable material for this purpose having been found to be a No. 30 S. A. E. lubricating oil. The mixture is made up preferably to about the consistency of a cooking porridge, 40 pounds of abrasive being thoroughly intermixed in 1 gallon of the vehicle, and sufficient quantity of the suspension is placed in the pot so that when raised to its uppermost position the upper surface of the top gear or article being treated Will be submerged in operation to a depth of about one-half to one inch.

In the burring or smoothing of an article in accordance with this invention several operations are usually involved. Where the article is symmetrical in shape, it is found desirable to subject the article to relative movement through the abrasive suspension for a definite period of time in one direction, and then to reverse the direction of motion and to continue in the reverse direction for a similar length of time. This develops a similar action on corresponding surfaces of the article, and by suitable selection of the characteristics of the suspension itself. the fneness and abrasive quality of the suspended abrading material, the closeness of approach of a stationary wall to impede the rotation of the suspension with the article, and the actual time and speed of rotation, it is possible to control and predetermine in large measure the location, characteristics, and extent of the smoothing action which is produced.

The machine may be conveniently controlled manually, or in part manually and in part automatically. It has been found desirable, however, to provide time controls for definitely predetermining the length of time during which the article is rotated while in the abrasive solution, since the continuance of such action for a prolonged period of time may lead to excessive abrading of working portions of the surface of the article, rendering it either damaged or unt for use. However where a definite time control is provided which will assure the stoppage of the action within a definite and controlled period of time, the possibility of the action being allowed to continue inadvertently for an excessive period of time is largely overcome. In actual practice it is found important to control the time limits quite accurately, as measured in terms of seconds, in order to develop the desired action, and to assure proper uniformity for a series of articles.

If desired the air supply valves for controlling the air supply to cylinders 92 and 95 may be controlled by hand, and likewise the gear shifting and reversing mechanism may be manually operated. In such manual operation, as will be clear from the foregoing, the work spindle 8| receives one or more of the articles to beftreated. Both control valves 93 and 9E are then opened to cause the raisin'g'of the pot 90 to a position in' which the articles are submerged beneath the surface of the abrasive solution. The start button |00 may then be pressed to close a suitable energizing circuit vfor the motor. A second start button |0| may be provided for initiating the rotation of the spindle, causing the energizing of the clutch and concurrent release of the brake with resultant driving of the work.

The Work shaft is thus caused to rotate, and such operation is continued for a definite period of time after which the clutch is deenergized and the brake applied to stop the spindle. Thereupon the vplate 59 may be swung manually to its other alternative position, establishing a driving connection to rotate the work spindle in the opposite direction.l Upon subsequent operation of push Ibutton IUI, the work spindle then revolves for a predetermined period of time in the opposite direction and is again brought to a stop at the end of that period.

One of the air valves, 95, may then be closed resulting in the lowering of the pot from the c position to the b position where the work is above the liquid level but still within the upper rim of the pot. The work is then rotated for a short period of time sufficient to throw off the bulkY of the adhering suspension under the action of centrifugal force. The remaining air valve 93 is then closed, and the spindle stopped, whereupon the finished article may be removed and the device is in condition for a subsequent cycle of operation.

Preferably the mechanism is arranged for control over an entire cycle of operations, suitable electrical relays being provided and assembled on the frame of the machine in a housing |05 provided for that purpose. The operation of the system is based upon the use of a group of time-controlled relays (TRI, TR2, TRS and TRA) which are sequentially energized, and the time intervals of which may be individually controlled (by means of the respective -micrometer adjusting dials A, B, C and D) in order to provide complete exibility of adjustment for all positions 0f the operating cycle. Any suitable timing devices may be used an example of a suitable type being the Square D Company Class 9050 timing relays.

Referring to Fig, 9 which shows a wiring diagram of the overall control mechanism the main drive motor I6 is shown as energized from a three phase power source l0 through overload fuses and contactors |2a. The control circuits are energized from a single phase source of supply as shown at I3.

For this purpose a normally closed stop button I4 provides a connection to the start button |00, so that upon depression of the start button, relay ||2 is energized, thereby eiecting the closing of its contacts ||2a to close the main circuit to the drive motor. The switch contacts I|2b are also closed at the same time to establish a holding circuit luy-passing the start button |00, so that the drive motor will remain energized until the operation of stop button H4.

The drive motor having thus been placed in operation, the articles are properly mounted upon the work spindle 8|. When this has been completed, the operator then presses the start button |0| which places the machine in operation, the operation continuing without further attention on the part of the operator throughout an entire operating cycle.

In response to the operation of the push button |0| tostartthe cycle, an `energizing circuit tion within one of the larger diameter pots and functions to control the rotation of the suspension therein, in place of using a smaller diameter pot. Where it is desired to treat a gear cluster including gears'or surfaces of relatively large and small diameter axially spaced from each other, the use of a baffle such as shown in Fig. 8 is particularly advantageous. As shown the arms may be suitably shaped to provide inwardly extending projections |32 to afford desired clearance with respect to an upper smaller diameter gear aswell as with respect to a lower larger diameter gear, the arms being suitably shaped in each instance to provide the desired clearance with respect to all portions of the article under treatment.

Using the suspension medium above described and in the treating of precision gears of a hardness of about 38 Rockwell C, speeds of 3,000 to 3,500 R. P. M. have been successfully used with a time interval in each direction of 10 to 15 seconds, the uppermost gear or article under treatment being covered While in the pot to a depth of about A2 to 1 inch. Work of different hardness and grain structure has been found to require suspensions'of different kinds and grades of grit or abrasive, and the foregoing are mentioned only as examples which have given satisfactory results.

If desired agitation may be provided in the pot, this being suit-ably effected by the supplying of compressed air to the bottom part thereof as shown at |35, in order to maintain the solution well mixed. Such agitation is also advantageous in that it reduces the strain on the supporting arbor, and somewhat reduces the starting torque required to start the rotation of the spindle.

The invention thus provides a simple and highly reliable machine for effecting uniformly and rapidly what has heretofore required long drawn out individual work to perform at all, and which could not be done under conditions assuring a high degree of uniformity. By suitably varying the character and consistency of the material in the tank, the time during which the operation continues, and the closeness of approach of the stationary parts of the pot to the article being treated, substantially complete and accurate control can be secured over both the extent of the smoothing and burring operation, as well as over the particular parts or area in which that action is made effective. Careful tests have shown that when controlled in this manner the burr can be completely removed from around the edge of the teeth of a series of gears mounted on the work spindle, while the working faces of the teeth are left almost completely without change, the suspension appearing to contact the edges of the teeth but primarily remaining out of working contact with the actual face of the teeth due to the centrifuga1 forces involved. As will be clear, the rotation at higher speeds provides for increasing such centrifugal effect, and thus in conjunction with the other factors above described makes i1; possible to obtain proper predetermined action over the article as desired.

While the processes and forms of apparatus herein described constitute preferred embodiments of the invention it is to be understood that the invelntion is not limited to these precise processes and forms of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A machine for smoothing and removing burrs and the like from an article which comprises a container for receiving a quantity of abrasive in iluid suspension, a support having means thereon for receiving the article, means for moving said support with said article attached thereto relative to said fluid suspension for a period of time sufficient to effect the smoothing and burr removal therefrom, and a baille removably positioned in said container and projecting upwardly in predetermined relation to said article.

2. A. machine for smoothing and removing burrs and the like from an article which comprises a container for receiving a quantity of abrasive in fluid suspension, a. support having means thereon for receiving the article, means for rotating said support with said article attached thereto in said fluid suspension for a.A period of time sufficient to effect the smoothing and burr removal therefrom, and removable means receivable in said container in predetermined operative relation with said article and constructed to limit the movement of a fluid in said container with respect to the container.

3. A machine for smoothing and removing burrs and the like from an article which comprises a container for receiving a quantity of abrasive in thick fluid suspension, the inner vertical dimension of said container being substantially greater than the vertical dimension of the article to be treated, the quantity of suspension in said container being controlled to a depth sufficient to receive said article therein while leaving space within the container and above the level of the suspension suilicient to receive said article therein, a support having means thereon for receiving the article, means for moving said container relative to said support to immerse the article in said suspension, means for rotating said support with said article attached thereto in said suspension, and means for moving said container relative to said support to cause withdrawal of the article from said suspension While remaining within the confines of said container to provide for the throwing off of said suspension material from the article under the action of centrifugal force and for the retention of said material within said container.

4. A machine for smoothing and removing burrs and the like from an article which comprises a container for receiving a quantity of abrasive in thick fluid suspension, the inner vertical dimension of said container being substantially greater than the vertical dimension of the article to be treated, the quantity of suspension in said container being controlled to a depth sufficient to receive said article therein while leaving space within the container and above the level of the suspension sufficient to receive said article therein, a support having means thereon for receiving the article, means for moving said container relative to said support to immerse the article in said suspension, means for rotating said support with said article attached thereto in said suspension, and means to withdraw the article from the suspension and from said container in a plurality of stages including a i'lrst stage in which the article rotates 'within the connes of the container above the level of the-suspension to throw off said suspension material against the inner walls of the container, and a second stage in which the article is clear of the container.

5. A machine -for smoothing and removing 11 burrs and the like from an article which comprises a container for receiving a quantity of abrasive in fluid suspension, a support having means thereon for detachably receiving the article, means for rotating said support with said larticle attached thereto in said fluid suspension for a period of timer sufficient to effect the smoothing and burr removal therefrom, means for reversing the direction of rotation of said support, and means for controlling the length of time of rotation of said article in said suspension in both directions of rotation.

6. A machine for smoothing and removing burrs and the like from an article which comprises a container for receiving a quantity of abrasive in thick fluid suspension, a support having means thereon for receiving the article, means for raising the container'to immerse the article within said suspension, means for rotating said article while immersed in said suspension, and control means for correlating the rotation of said article with the raising of said container providing for the beginning of such rotation con-` currently with the'raising of the container.

' 7. A machine for smoothing and removing burrs and the like from an article which comprises a container for receiving a quantity of abrasive in fluid suspension, the inner vertical dimension of said container being substantially greater than thev vertical dimension of the article to be treated, the quantity of suspension in Vsaid container'being controlled to a depth sufficient to receive said article therein while leaving space Within the container and above the level of the suspension suflicient to receive said article therein, a support having means thereon for receiving the article, means for raising the container to immerse the article within the suspension, means for rotating saidarticle while immersed in abrasive smoothing contact WithY said suspension, means for lowering said container to Withdraw the article from said suspension while leaving the same Within the confines of the upper Wall of said container, and means for rotating said article for a predetermined period after Withdrawal from said suspension to provide for the throwing off of said suspension material from said article underV the action of centrifugal force and for the retention of said material Within said container.

8. A machine Vfor smoothing andv removing burrs and the like from an article which comprises a container for receiving a quantity of abrasive in fluid suspension, the inner vertical vdimension of said container being substantially greater than the vertical dimension of the article to be treated, the quantity of suspension in said container being controlled to a depth suilicient to receive said article therein while leaving space within the container and above the level of the suspension suiicient to receive said article there-V in, a support having means thereon for'receiving ltile article, means for raising the containerto imerse the articlewithin the suspension, means for rotating said article while immersed in abrasive smoothing contact with said suspension, means for lowering said container to withdraw the article from said suspension VWhile leaving the same within the confines of the upper wall of said container, means for rotating said article for a predetermined period after withdrawal from said suspension to provide for the throwing off of said suspension material from said article under the action of centrifugal force and for the retention of said material Within said containen'and nmeans to thereafter return lthe Acontainer to its fully lowered position -Y leaving thereof for removal;

9. A machine forsrnoothing and removing burrs andthe like from an Varticle which comthe article clear prises a container Vfor receiving a quantity ofk l sion,`control means for correlating'the 'rotation of said article with the movementA of said container providing for the beginning of such rotation concurrently with the raising of the con-- tainer, means for timing the period of rotation of the article While immersed 'to` eiiect removal of' rough parts and burrs therefrom without adverse- 1y Vaiecting the working surfaces ofthe article, means "for partially lowering the container'to remove the article from the liquid While leaving it Within the confines of the upper wall of the container, meansfor rotating said article in said removed position tofree the same of said suspension, and means to thereafter return the container to its fully lowered position leaving the article clear thereof for removal from said support,

`1G. The process of smoothing and removing burrs and the like from a gear wheel which. comprises. immersing the gear inV a relatively thick andviscous suspension of abrasive, rotating said gear Vat high speed whilevso immersed rfor a sufli- ,cient time to effect the smoothing and removal Vof yburrs therefrom, and thereafter withdrawing said gear from said suspension andv rotating the same at high speed'to clean the'gear by throwing on' `therefrom said suspension material.

11. The process ofsmoothing and removing burrsand the like from a gear wheel which comprises immersing the gear in a relatively thick and viscous suspension of abrasive, rotating said gearabout its own axis in one direction While so immersed-then rotating said gear in the opposite direction while so immersed, and controlling the lengthy `of rotation in each direction to effect vburrremoval without abrading the adjacent sur-- faces of theV teeth of said gear. y 1 12. The process of smoothing and removing burrs and the `like from agear wheel which comprises immersing the gear in a relatively thick and viscous suspension of abrasive, rotating the article while so immersed for a suflicient time to effect the smoothing and removal of burrstherefrom, and controlling the time and the speed and direction. of rotation to predetermine the smoothing and burring action 'which'is produced and tov effect burr removal without abrading the adjae cent surfaces of the teeth of said gear.

- RODMAN C. PRUI'II. Y

EDWARD F. FOWLE. ,RICHARD S. IGLEI-IART.

REFERENCES CI'IED` "The following references are of record inthe iilexof this patent: l

Scherer ll Jan. 6,1942 

